8 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Grinnell | 1 | 9,474 | 9,537 | -0.11% | 1,665 | 6 | City |
| Brooklyn | 2 | 1,461 | 1,499 | -0.41% | 1,111 | 1 | City |
| Montezuma | 3 | 1,409 | 1,445 | -0.42% | 570 | 2 | City |
| Malcom | 4 | 252 | 267 | -0.79% | 305 | 1 | City |
| Deep River | 5 | 241 | 247 | -0.41% | 551 | 0 | City |
| Searsboro | 6 | 128 | 130 | 0% | 284 | 0 | City |
| Hartwick | 7 | 90 | 92 | 0% | 570 | 0 | City |
| Guernsey | 8 | 58 | 61 | 0% | 103 | 1 | City |
Grinnell is the largest city in Poweshiek County, with a population of 9,474.
Guernsey is the smallest city in Poweshiek County, with a population of 58.
There are 8 cities in Poweshiek County, Iowa.